CN109402500A - The hot-bending bends of low-temperature good toughness X80 Wide and Heavy Plates and its production method - Google Patents
The hot-bending bends of low-temperature good toughness X80 Wide and Heavy Plates and its production method Download PDFInfo
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/02—Ferrous alloys, e.g. steel alloys containing silicon
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0205—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips of ferrous alloys
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0221—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the working steps
- C21D8/0226—Hot rolling
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- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D8/00—Modifying the physical properties by deformation combined with, or followed by, heat treatment
- C21D8/02—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips
- C21D8/0247—Modifying the physical properties by deformation combined with, or followed by, heat treatment during manufacturing of plates or strips characterised by the heat treatment
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/001—Ferrous alloys, e.g. steel alloys containing N
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/06—Ferrous alloys, e.g. steel alloys containing aluminium
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- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/42—Ferrous alloys, e.g. steel alloys containing chromium with nickel with copper
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/44—Ferrous alloys, e.g. steel alloys containing chromium with nickel with molybdenum or tungsten
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/46—Ferrous alloys, e.g. steel alloys containing chromium with nickel with vanadium
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- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
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- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/48—Ferrous alloys, e.g. steel alloys containing chromium with nickel with niobium or tantalum
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C38/00—Ferrous alloys, e.g. steel alloys
- C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
- C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
- C22C38/58—Ferrous alloys, e.g. steel alloys containing chromium with nickel with more than 1.5% by weight of manganese
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- C—CHEMISTRY; METALLURGY
- C21—METALLURGY OF IRON
- C21D—MODIFYING THE PHYSICAL STRUCTURE OF FERROUS METALS; GENERAL DEVICES FOR HEAT TREATMENT OF FERROUS OR NON-FERROUS METALS OR ALLOYS; MAKING METAL MALLEABLE, e.g. BY DECARBURISATION OR TEMPERING
- C21D2211/00—Microstructure comprising significant phases
- C21D2211/002—Bainite
Abstract
The present invention provides hot-bending bends X80 Wide and Heavy Plates and its production method of a kind of low-temperature good toughness, steel plate ingredient C:0.055%~0.080%, Si:0.16%~0.35%, Mn:1.55%~1.75%, Nb:0.025%~0.050%, Ti:0.011%~0.025%, V:0.05%~0.09%, Cr:0.21%~0.45%, Mo < 0.20%, Ni < 0.25%, Cu < 0.20%, Al:0.010%~0.035%, P≤0.010%, S≤0.002%, N:0.001%~0.004%, surplus are iron and inevitable impurity.Production method: molten iron pretreatment, converter smelting, external refining, continuous casting, heating, rolling, cooling, heat treatment；Microstructure: bainite+ferrite.
Description
Technical field
The invention belongs to low-carbon low-alloy steel field more particularly to a kind of low temperature environment oil-gas transportation hot-bending bends are thick
Degree >=26mm, width > 4300mm X80 grade Wide and Heavy Plates and its production method.
Background technique
In order to improve the transfer efficiency of oil-gas pipeline, discharge pressure and pipe diameter are continuously increased；To take into account conduit running
Safety, it is desirable that corresponding oil-gas pipeline steel is to high intensity, heavy wall, the development of big plate width direction.Meanwhile with oil-gas pipeline
Construction constantly extends to the active area of outlying, cold, geology and the increasing of the particular surroundings steel for pipe demands such as low temperature yard
More, the technical indicators such as low-temperature flexibility, anti-plastic degeneration (high-ductility, low yield strength ratio) of oil-gas pipeline steel are constantly taken seriously,
Therefore, the product for having both the features such as high intensity, high tenacity, low yield strength ratio, generous specification is the important side of steel for pipe development
To.
Hot-bending bends are the important feature parts in oil-gas pipeline, play and change duct orientation, buffering strain and torque and mistake
The effects of strong matching protection, use condition is increasingly complex compared with main line pipe, and therefore, the wall thickness of usual hot-bending bends is greater than main line
Pipe, moreover, having excellent comprehensive performance.Hot-bending bends of the present invention its thickness >=26mm of Wide and Heavy Plates, width >
4300mm.The feature of heavy wall makes to accelerate cooling effect decrease, the refinement of mid-depth tissue around and the Uniform Control more tired
It is difficult；To finally significantly increase Properties Control difficulty；Meanwhile with the increase of width, in identical implementation condition and equipment
Under ability, steel plate rolling deformability is seriously restricted, crystal grain refinement and control difficulty multiplication；Therefore, for low temperature environment
For heavy wall, the wide steel for hot-bending bends plate of big plate, how to be obtained in the case where deforming and the techniques such as cooling are restricted
Good comprehensive performance and steel-plate shape be the invention solves one of critical issue.In addition, since hot-bending bends are forming
Heat treatment process is undergone in the process, and therefore, steel for hot-bending bends also needs to have good heat resistance, after guaranteeing heat treatment
Still there is good comprehensive performance.
The technical indicator that the effective Wide and Heavy Plates of X80 grade low-temp ambient heat simmering and bending are generally configured with includes horizontal and vertical surrender
Intensity >=555MPa, horizontal and vertical tensile strength >=655MPa, horizontal and vertical elongation percentage >=21% are horizontal and vertical to bend
Strong ratio≤0.85, -55 DEG C of horizontal V-shape notch Charpy-V impact power >=180J；Meanwhile the size characteristic wide with heavy wall, big plate.
Currently, there are some researchs to oil-gas transportation bend pipe steel plate both at home and abroad, the related patent in part is had found through retrieval
And document, but its documented content and the side such as technical solution of the present invention and the product category, ingredient, technique and performance
There are notable differences in face, do not influence creativeness and novelty of the invention.
The related patents and document retrieved are as follows:
It is public to invent " high-ductility steel for hot-bending bends and its hot rolled slab production method " (publication number: CN101161847A)
A kind of X70, X80 grade of steel for hot-bending bends is opened, ingredient is designed using more Mo, Nb, Cu element, and cost of alloy is high, is only protected
- 20 DEG C of impact flexibility are demonstrate,proved, yield tensile ratio is high, is unsatisfactory for low temperature environment steel for hot-bending bends and wants to low-temperature flexibility, anti-plastic degeneration
It asks.
Invention " high-ductility steel for hot-bending bends rolling mill practice " (publication number: CN107385340A) discloses X80 grades a kind of
The rolling mill practice of steel for hot-bending bends, the X80 grades of steel for hot-bending bends width are less than 2600mm, are unable to satisfy the big mouth of manufacture
The requirement of diameter hot-bending bends；Using more valuable conjunctions such as Ni:0.60%~0.70%, Mo:0.28%~0.32% in ingredient
Gold, high production cost；Big pass deformation rate and ultra-rapid cooling are used in technique, and harshness is proposed to capacity of equipment and is wanted
It asks, is not suitable for the production of ultra-wide heavy wall steel for hot-bending bends.
Invention " a kind of X65-X80 rank hot-bending bends Wide and Heavy Plates and its manufacturing method " (publication number:
CN104404378A steel plate width disclosed in) is less than 3800mm, only guarantees -20 DEG C of impact flexibility, yield tensile ratio is higher, is unsatisfactory for
The requirement of low temperature environment heavy caliber steel for hot-bending bends.
Invention " a kind of low temperature resistant bend pipe of X80 steel and its manufacturing process " (publication number: CN102268612A) has disclosed one
X80 grades of hot-bending bends of kind, equally there is the deficiencies of cost of alloy is high, product yield tensile ratio is high.
Invention) " a kind of superhigh intensity bend pipe of low-temperature good toughness " (publication number: JP2005350724 (A) is provided
A kind of X100-X120 grades of bend pipe, equally improves performance by precious alloys such as Ni, Mo and yield tensile ratio is high.
Document " influence of the heating temperature to X80 steel-grade hot-bending bends structure property " (" welded tube " 6 phases of volume 37 in 2014,
Tian Chenchao, Xu Fei, coke are of heap of stone etc.), a kind of influence of X80 hot-bending bends and heating process to it, the heat are mainly described in text
Simmering and bending pipe ingredient is using conventional addition Mo, Ni, Cu alloy design, and there is also the higher problems of yield tensile ratio.
In conclusion the prior art still has some deficits to the research of generous specification low temperature environment steel for hot-bending bends.
Summary of the invention
It is an object of the invention to overcome the above problem and it is insufficient and provide a kind of low temperature environment hot-bending bends thickness >=
26mm, width > 4300mm X80 grade ultra-wide, heavy wall, high intensity, high tenacity, low yield strength ratio, high plasticity hot-rolled steel plate and its life
It is comprehensive to solve low temperature environment steel for hot-bending bends plate intensity, low-temperature flexibility, anti-flow, heat-treatability stabilizability etc. for production method
Performance Match problem and width, thickness increase the problems such as bring technique is limited, structure property control is difficult.
The present invention is implemented as follows:
Thickness >=26mm of the hot-bending bends of low-temperature good toughness of the present invention X80 Wide and Heavy Plates, width >
4300mm；Ingredient designs based on low C, low Mn, emphasis Mo, Nb, the Ni valuable using V, Cr element portions or replacing whole
Equal elements, guarantee the strength of materials and toughness；Crystal grain and precipitation are refined in deformation and heat treatment process using elements such as V, Nb
Invigoration effect promotes structure refinement and homogenization, improves obdurability, heat resistance and welding performance；Be equipped with targetedly smelt,
The production technologies such as heating, rolling, cooling and unique heat treatment, which obtain, has ultra-wide, heavy wall, high intensity, low yield strength ratio, high-ductility
The steel for hot-bending bends plate and ideal microstructure morphology of excellent overall target with good low-temperature flexibility etc..
A kind of hot-bending bends of low-temperature good toughness X80 Wide and Heavy Plates, the ingredient of the steel plate is by weight percentage such as
Under: C:0.055%~0.080%, Si:0.16%~0.35%, Mn:1.55%~1.75%, Nb:0.025%~
0.050%, Ti:0.011%~0.025%, V:0.05%~0.09%, Cr:0.21%~0.45%, Mo < 0.20%, Ni <
0.25%, Cu < 0.20%, Al:0.010%~0.035%, P≤0.010%, S≤0.002%, N:0.001%~
0.004%, wherein (Mo+Ni+Cr+Cu): 0.40%~0.70%, surplus is iron and inevitable impurity；And CEIIWControl
In 0.43%~0.49%, CEPcmControl is 0.18%~0.22%, wherein CEIIW=C+Mn/6+ (Cr+Mo)/5+ (Ni+
Cu)/15；
CEPcm=C+Si/30+ (Mn+Cu+Cr)/20+Ni/60+Mo/15+V/10+5B.
Further, the steel plate microstructure be bainite+ferritic complex tissue, grain size reach 11 grades and with
On, wherein ferrite percentage is 8%~35%.
Further, the steel plate thickness >=26mm, width > 4300mm, horizontal and vertical yield strength >=560MPa are horizontal
To with endwise tensile strength >=670MPa, horizontal and vertical elongation percentage >=40%, horizontal and vertical yield tensile ratio≤0.82, -60 DEG C
Side knock function mean value >=240J.
It is as follows that present component designs reason:
C is effective intensified element, is capable of forming interstitial solid solution, improves intensity after harden ability and heat treatment；It can be with
Tiny carbide is formed with element interactions such as Nb, V, Ti, is precipitated, plays in slab heating, deformation and steel plate heat treatment process
Crystal grain is hindered to grow up, the effect of thinning microstructure；Precipitated phase can hinder dislocation mobile simultaneously, effectively improve intensity, therefore, carbon
Content is unsuitable too low；But, it is contemplated that the increase of carbon content is unfavorable to weldability and toughness, especially impaired low temperature toughness, institute
With carbon content can not be excessively high, it is considered herein that carbon control is more suitable for 0.055%~0.080%.
Si mainly plays solution strengthening effect in the present invention, improves harden ability, to raising controlled rolling and controlled cooling state and heat treatment
State intensity has positive effect；But its too high levels can be such that the plasticity of steel and toughness reduces, and easily cause cold short, optimum range is
0.16%~0.35%.
Mn has solution strengthening effect, and harden ability can be improved, advantageous to intensity after guaranteeing heat treatment；It can also increase
Stabilization of austenite reduces austenite transition temperature, and the phase transformation and crystal grain before inhibiting laminar cooling process are grown up, and plays refinement
Crystal grain effect；But the excessively high easy induction segregation of manganese content, deteriorate thick steel sheet structural homogenity and mid-depth toughness and not
Conducive to welding, it is considered herein that being more suitable for 1.55%~1.75% by manganese content control.
Nb has apparent solid solution and precipitation strength effect, and the present invention makes full use of Nb in rolling, accelerates at cooling preceding and heat
Precipitation pinning ability during reason, effectively refinement crystal grain improve intensity and improve toughness, meanwhile, Nb can inhibit austenite again
Crystallization improves recrystallization rolling temperature, thus, roll-force is effectively reduced, it is curved to raising ultra-wide of the present invention, heavy wall fire bending
The rolling pass deformation rate of effective steel plate reaches expected fine grain effect and plays a positive role；In addition, Nb can also reduce thickness
Wall pipe line steel when rolling thickness direction temperature difference due to the mixed crystal problem that generates, still, Nb too high levels can make production cost
It obviously increases, moreover, precipitate can be promoted to grow up, is unfavorable for playing invigoration effect instead, have an adverse effect to toughness, this
Invention is thought to control Nb content.
Ti can play nitrogen fixation effect, form the precipitated phase based on TiN, can inhibit the crystalline substance of austenite under hot conditions
Grain length is big, is conducive to refine slab and steel plate microstructure, can also improve postwelding heat affected area toughness；Meanwhile Ti is in high temperature
Lower formation precipitated phase can reduce N, C concentration, inhibit the precipitations of elements at high temperature such as Nb, V, make it easily at lower temperatures
Tiny precipitated phase is formed, to be more advantageous to raising performance.It is considered herein that Ti content is controlled 0.011%~0.025%
More it is suitable for.
V has solid solution and precipitation effect, and when solid solution can effectively improve intensity；And its Precipitation Temperature is lower than based on Nb, Ti
Precipitated phase, tiny precipitation can be formed in conjunction with C, N in rolling, cooling and heat treatment process, especially be heat-treated when have
There is post-curing effect, increase resistance to tempering ability, guarantees performance after heat treatment.Emphasis of the present invention is special with the both the above of V
Property is effectively improved comprehensive performance.But V content is excessively high to will affect steel plate and hot-zone toughness, and therefore, the present invention controls V content
0.05%~0.09%.
Cr can improve stabilization of austenite and harden ability, reduce austenite transition temperature, refine crystal grain, guarantee heat treatment
Performance afterwards plays good action to improving thick steel sheet intensity and improving thickness direction structural homogenity；There are also solution strengthening by Cr
Effect, it is advantageous to proof strength；Meanwhile Cr can reduce the diffusivity of C, improve heat-treatability stabilizability, promote Nb,
The refinement of V precipitated phase；Moreover, Cr element economy is high, the expensive alloying elements such as Mo, Ni can be partially substituted；The present invention is abundant
The above characteristic of Cr is utilized to effectively improve the comprehensive performance of product；But Cr too high levels are unfavorable to weldability, and plasticity also has
Degradating trend, so, Cr content control 0.21%~0.45% is advisable.
Mo can increase stabilization of austenite, hence it is evident that improve harden ability, cryo tissue transformation in promotion increases intensity, also
The structure property of steel plate and the area HAZ can be optimized, still, the excessively high one side of molybdenum content will increase cost, on the other hand, can increase
M/A in tissue etc. is added to harden phase, therefore its content should be controlled below 0.20% by reducing toughness.
Ni plays solution strengthening effect, is conducive to improve low-temperature flexibility；Middle temperature transformation can also be promoted to organize the formation of, dropped
Low thick steel plates cooling rate limitation；But nickel price is higher, and therefore, its content is controlled to be advisable < 0.25%.
Cu can play solution strengthening effect, meanwhile, it is capable to reduce the diffusivity of C, improve heat-treatability stabilizability,
Cu can also improve corrosion resistance, but Cu too high levels easily induce crackle, weldability be damaged, it is considered herein that by copper content control
More it is suitable for < 0.20%.
Al is deoxidant element, also has stronger combination trend with N, and AlN can improve welding hot-zone toughness；But Al contains
The excessively high increase that can promote field trash is measured, the present invention controls Al 0.010%~0.035%.
P, S is objectionable impurities elements in the present invention, and the lower content the better；Wherein, P has significantly not low-temperature flexibility
Benefit influences, and P control can be promoted the generation of field trash in the increase of≤0.010%, S content and grown up by the present invention, deteriorates performance,
Therefore, S≤0.002%.
N can form precipitate in conjunction with the elements such as Nb, V, Ti, to inhibit when heating of plate blank crystal grain grow up plays it is obvious
Effect, meanwhile, precipitation strength effect can be played in rolling, cooling and heat treatment process, therefore, there are certain N pairs in steel
Performance is advantageous, but too high levels can deteriorate the toughness of base material and welding heat affected zone, content control 0.001%~
0.004% is advisable.
Mo, Ni, Cr, Cu all have invigoration effect, increase stabilization of austenite, are conducive to improve harden ability and heat treatment
Performance afterwards, Mo+Ni+Cr+Cu is too low to be unfavorable for performance and microstructure control, and too high levels influence weldability and economy, because
This, the present invention is by (Mo+Ni+Cr+Cu): 0.40%~0.70%.
The present invention is by CEIIWControl is in 0.43%~0.49%, CEPcmControl can both guarantee 0.18%~0.22%
The obdurability of steel plate, and can make steel plate that there is suitable solderability.
The two of technical solution of the present invention are to provide a kind of life of the hot-bending bends X80 Wide and Heavy Plates of low-temperature good toughness
Production method, including molten iron pretreatment, converter smelting, external refining, continuous casting, heating, rolling, cooling, heat treatment；
(1) continuous casting: the Argon calmness time is no less than 10min before continuous casting after liquid steel refining, continuous casting billet be poured the degree of superheat 15~
35 DEG C, continuous casting billet pulling rate 0.6m/min-1.0m/min, thickness of strand/finished steel plate thickness control is in 7-12；Before continuous casting
Argon calmness can be improved the uniformity of liquid steel temperature and ingredient, be conducive to the floating removal of field trash；It is poured the degree of superheat and company
The control of Casting speed can effectively reduce slab quality defect；Compression ratio from continuous casting billet to finished steel plate is conducive to crystal grain
Refinement.
(2) heat: continuous casting billet shove charge after clearing up is heated, using two stages heating method, wherein high-temperature heating Duan Wen
1180~1220 DEG C of degree, 1160~1200 DEG C of soaking section temperature, high-temperature heating section+soaking zone time is not less than 120min；Continuous casting
Base cleaning can effectively reduce surface defect, and the design of heating process is allowed to mainly for the solid solution of guarantee alloying element subsequent
Ideal effect is played in production, meanwhile, effectively control Austenite Grain Growth；Heating time can guarantee heating effect and temperature
Spend uniformity.
(3) roll: roughing start rolling temperature is 1090~1140 DEG C, and roughing finishing temperature is 970~1020 DEG C, using cross
Vertical rolling mode, wherein axial rolling start temperature is lower than 1060 DEG C, and the axial rolling stage guarantees the passage deformation of at least last 2 passages
Rate is greater than 15% and road minor tick is no more than 15s；Roughing mill speed 1.2m/s-2.0m/s；The rolling temperature of rough rolling step and
Deformation technique recrystallizes austenite grain, and roughing axial rolling latter end can take into account equipment using big pressure and short spacer process
Deformation Overlay is preferably played under the premise of ability, rolling load, promotes austenite to recrystallize, it is thin to reach crystal grain
Change target, the production of ultra-wide thick steel sheet of the present invention preferably, the control of roughing mill speed can promote rolling deformation to thickness
The infiltration at degree center refines mid-depth crystal grain, is conducive to the core structure for improving big wall thickness pipe line steel.
Intermediate temperature control plate blank thickness 3.1t~5.0t, wherein t is finished steel plate thickness, and finish rolling start rolling temperature is 820~880
DEG C, finish rolling finishing temperature is 750~780 DEG C；It on the one hand can guarantee using big intermediate temperature control plate blank thickness and low final rolling temperature
Austenite deformation simultaneously accumulates deformation energy, on the other hand, the induction of the tiny precipitated phase of Nb, V can be promoted to be precipitated, pinning crystal boundary
And dislocation, increase nucleation site, refines crystal grain；Furthermore tiny ferrite forming core can also be promoted.
(4) cooling: to roll rear steel plate and carry out acceleration water cooling, start 720~750 DEG C of cooling by water temperature, final cooling temperature 330
~450 DEG C, 8~20 DEG C/s of cooling by water speed, the cooling by water time is not less than 15s.Due to the elements energy such as Cr, Mn, Mo, Cu
Austenite transition temperature is enough reduced, it is therefore possible to use lower begin to cool temperature, is conducive to the refinement of crystal grain and tiny
The formation of precipitate；It, can be using lower cooling velocity and longer cold moreover, because alloying element improves harden ability
But the time reduces steel plate internal stress, that is, is able to satisfy performance again to increase the cooling uniformity of thick steel sheet thickness direction
The influence to plate shape can be reduced.
(5) be heat-treated: 820~870 DEG C of hardening heat of control, 0.5 min/mm of Quenching Soaking Time~1.0min/mm quenches
Fire can effectively inhibit crystal grain while obtaining polygonal ferrite+austenite complex tissue using low-temperature heat technique
Grow up；Cooling velocity >=15 DEG C/s is quenched, is cooled to room temperature, the hard phase of polygonal ferrite+bainite, M/A are obtained；It returns
350~500 DEG C, tempering insulation time 0.7min/mm~1.4min/mm of fiery temperature, promotes precipitation strength and temper hardening, mention
High-yield strength reduces residual stress, meanwhile, the excessive precipitation of element and growing up for bainite crystal grain are prevented, is guaranteed strong
Degree.
Microstructure is based on bainite+ferritic complex tissue after steel plate heat treatment, wherein ferrite hundred
Point than 8%~35%, grain size reaches 11 grades of grades or more, and steel plate has ultra-wide, heavy wall, high intensity, low yield strength ratio, high-plastic
Property and good low-temperature flexibility, meanwhile, weldability and mouldability meet the requirement of production X80 grades of hot-bending bends of ultra-wide heavy wall.
A kind of production method of the hot-bending bends of low-temperature good toughness X80 Wide and Heavy Plates of the present invention is ideal by obtaining
Internal soundness, the crystal grain that reduces harmful element and effectively refine steel plate after controlled rolling and controlled cooling while impurity, control precipitated phase,
To which tissue and structure after refining and controlling heat treatment by tissue heredity and suitable heat treatment process guarantee heat
Performance that treated.
The beneficial effects of the present invention are:
(1) based on low C, low Mn, emphasis is valuable using V, Cr element portions or replacing whole for present component design
The elements such as Mo, Nb, Ni, guarantee the strength of materials and toughness；Crystalline substance is refined in deformation and heat treatment process using elements such as V, Nb
Grain and precipitation strength effect, promote structure refinement and homogenization, improve obdurability, heat resistance and welding performance；It is equipped with therewith
Corresponding unique production technology makes low temperature environment ultra-wide heavy wall steel for hot-bending bends plate obtain ideal heterogeneous microstructure, thin
Small crystal grain, excellent comprehensive performance and good profile.
(2) carbon equivalent ce of the present inventionIIWAnd CEPcmIt is suitable for guaranteeing that material has good intensity and solderability.
(3) refining of the invention, continuous casting process scheme effectively improve slab quality, to improve final products performance.
(4) present invention using unique low temperature low speed it is short interval roll+roll rear low temperature it is long when uniformly control cold+low temperature quenching
And tempering process, give full play to the effects of alloying element reduces phase transition temperature, improves harden ability, fine grain is precipitated and strengthens and group
The compound matching effect of the heredity, multinomial tissue knitted obtains strong plasticity and toughness and matches good product, meanwhile, increase cooling
Uniformity reduces internal stress and structural stress, effectively controls the plate shape of steel plate.
(5) thickness >=26mm, width of the hot-bending bends of low-temperature good toughness of the present invention X80 Wide and Heavy Plates >
4300mm, horizontal and vertical yield strength >=560MPa, horizontal and vertical tensile strength >=670MPa, horizontal and vertical extension
Rate >=40%, horizontal and vertical yield tensile ratio≤0.82, -60 DEG C of side knock function mean value >=240J, microstructure be bainite+
Ferritic complex tissue, wherein for polygonal ferrite percent by volume 8%~35%, grain size reaches 11 grades of grades or more,
Meet the requirement of production X80 grades of hot-bending bends of low temperature environment ultra-wide heavy wall.
Specific embodiment
Below by embodiment, the present invention is further illustrated.
The embodiment of the present invention according to the component proportion of technical solution, carry out molten iron pretreatment, converter smelting, external refining,
Continuous casting, heating, rolling, cooling, heat treatment.
The ingredient of steel of the embodiment of the present invention is shown in Table 1.The smelting continuous casting heating technique parameter of steel of the embodiment of the present invention is shown in Table 2.
The roughing technological parameter of steel of the embodiment of the present invention is shown in Table 3.The finish-rolling process parameter of steel of the embodiment of the present invention is shown in Table 4.The present invention is real
The cooling technique parameter for applying a steel is shown in Table 5.Heat-Treatment of Steel technological parameter of the embodiment of the present invention is shown in Table 6.Steel of the embodiment of the present invention
Performance be shown in Table 7.The microstructure of steel of the embodiment of the present invention is shown in Table 8.
The ingredient (wt%) of 1 steel of the embodiment of the present invention of table
The smelting continuous casting heating technique parameter of 2 steel of the embodiment of the present invention of table
The roughing technological parameter of 3 steel of the embodiment of the present invention of table
The finish-rolling process parameter of 4 steel of the embodiment of the present invention of table
Note: t is finished steel plate thickness.
The cooling technique parameter of 5 steel of the embodiment of the present invention of table
| Embodiment | Start water cooling temperature, DEG C | Final cooling temperature, DEG C | Cooling by water speed, DEG C/s | Cooling by water time, s |
| 1 | 740 | 350 | 12 | 33 |
| 2 | 740 | 410 | 14 | 24 |
| 3 | 730 | 380 | 10 | 35 |
| 4 | 735 | 420 | 10 | 32 |
| 5 | 745 | 370 | 12 | 31 |
| 6 | 750 | 360 | 17 | 23 |
6 Heat-Treatment of Steel technological parameter of the embodiment of the present invention of table
| Embodiment | Hardening heat, DEG C | Quenching Soaking Time, min/mm | Tempering temperature, DEG C | Tempering insulation time, min/mm |
| 1 | 850 | 0.6 | 450 | 1.1 |
| 2 | 830 | 0.9 | 430 | 0.9 |
| 3 | 830 | 0.8 | 370 | 1.0 |
| 4 | 840 | 0.8 | 400 | 0.9 |
| 5 | 840 | 0.6 | 370 | 1.0 |
| 6 | 860 | 0.8 | 360 | 1.3 |
The performance of 7 steel of the embodiment of the present invention of table
Note: tensile sample is through thickness rectangular specimen, the wide 38.1mm of parallel testing section plate；Impact specimen is having a size of 10*55*
55mm。
The microstructure of 8 steel of the embodiment of the present invention of table
From the foregoing, it will be observed that the hot-bending bends X80 for the low-temperature good toughness for answering this technical solution disclosed by the invention to produce
Wide and Heavy Plates thickness >=26mm, width > 4300mm, horizontal and vertical yield strength >=560MPa, horizontal and vertical tensile strength
>=670MPa, horizontal and vertical elongation percentage >=40%, horizontal and vertical yield tensile ratio≤0.82, -60 DEG C of side knock function mean values >=
240J, microstructure are bainite+ferritic complex tissue, wherein polygonal ferrite percent by volume 8%~
35%, grain size reaches 11 grades of grades or more, meets the requirement of production X80 grades of hot-bending bends of low temperature environment ultra-wide heavy wall.
In order to state the present invention, explanation appropriately and is being sufficiently carried out to the present invention by embodiment among the above, it is above
Embodiment is merely to illustrate the present invention, and not limitation of the present invention, those of ordinary skill in related technical field,
In the case where not departing from the spirit and scope of the present invention, it can also make a variety of changes and modification, made any modification, etc.
With replacement, improvement etc., should all be included in the protection scope of the present invention, scope of patent protection of the invention should be wanted by right
Ask restriction.
Claims (4)
1. a kind of hot-bending bends of low-temperature good toughness X80 Wide and Heavy Plates, which is characterized in that the ingredient of the steel plate by weight hundred
Divide as follows than counting: C:0.055%~0.080%, Si:0.16%~0.35%, Mn:1.55%~1.75%, Nb:0.025%
~0.050%, Ti:0.011%~0.025%, V:0.05%~0.09%, Cr:0.21%~0.45%, Mo < 0.20%, Ni
< 0.25%, Cu < 0.20%, Al:0.010%~0.035%, P≤0.010%, S≤0.002%, N:0.001%~
0.004%, wherein (Mo+Ni+Cr+Cu): 0.40%~0.70%, surplus is iron and inevitable impurity；And CEIIWControl
In 0.43%~0.49%, CEPcmControl is 0.18%~0.22%, wherein CEIIW=C+Mn/6+ (Cr+Mo)/5+ (Ni+Cu)/
15；CEPcm=C+Si/30+ (Mn+Cu+Cr)/20+Ni/60+Mo/15+V/10+5B.
2. a kind of hot-bending bends X80 Wide and Heavy Plates of low-temperature good toughness according to claim 1, which is characterized in that
The steel plate microstructure is bainite+ferritic complex tissue, and grain size reaches 11 grades or more, wherein ferrite
Product percentage is 8%~35%.
3. a kind of hot-bending bends X80 Wide and Heavy Plates of low-temperature good toughness according to claim 1, which is characterized in that
Steel plate thickness >=the 26mm, width > 4300mm, horizontal and vertical yield strength >=560MPa, horizontal and vertical tensile strength
>=670MPa, horizontal and vertical elongation percentage >=40%, horizontal and vertical yield tensile ratio≤0.82, -60 DEG C of side knock function mean values >=
240J。
4. a kind of a kind of described in any item lifes of the hot-bending bends of low-temperature good toughness X80 Wide and Heavy Plates of claim 1-3
Production method, including molten iron pretreatment, converter smelting, external refining, continuous casting, heating, rolling, cooling, heat treatment, feature exist
In:
(1) continuous casting: the Argon calmness time is no less than 10min before continuous casting after liquid steel refining, and continuous casting billet is poured 15~35 DEG C of the degree of superheat,
Continuous casting billet pulling rate 0.6m/min-1.0m/min, thickness of strand/finished steel plate thickness control is in 7-12；
(2) heat: continuous casting billet shove charge after clearing up is heated, using two stages heating method, wherein high-temperature heating section temperature 1180
~1220 DEG C, 1160~1200 DEG C of soaking section temperature, high-temperature heating section+soaking zone time is not less than 120min；
(3) roll: roughing start rolling temperature is 1090~1140 DEG C, and roughing finishing temperature is 970~1020 DEG C, is rolled using transverse and longitudinal
Mode, wherein axial rolling start temperature is lower than 1060 DEG C, and the axial rolling stage guarantees that the pass deformation rate of at least last 2 passages is greater than
15% and road minor tick be no more than 15s；Roughing mill speed 1.2m/s-2.0m/s；
Intermediate temperature control plate blank thickness 3.1t~5.0t, wherein t is finished steel plate thickness, and finish rolling start rolling temperature is 820~880 DEG C, essence
Rolling finishing temperature is 750~780 DEG C；
(4) cooling: to roll rear steel plate and carry out acceleration water cooling, start 720~750 DEG C of cooling by water temperature, final cooling temperature 330~450
DEG C, 8~20 DEG C/s of cooling by water speed, the cooling by water time is not less than 15s；
(5) it is heat-treated: 820~870 DEG C of hardening heat of control, Quenching Soaking Time 0.5min/mm~1.0min/mm；It quenches cold
But speed >=15 DEG C/s, is cooled to room temperature；350~500 DEG C of tempering temperature, tempering insulation time 0.7min/mm~1.4min/
mm。
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